The four races of the Illendi live in relative cooperation in a set of nations inhabiting a single subcontinent, called Illendor, meaning “The High Land” or “The Great Land” in the Correll tongue.
The subcontinent Illendor lies on the eastern edge of a large continent Pharallon, and is separated from that continent by a mighty mountain range (think India and the Himalayas).
Because Illendor is a large subcontinent where the races live in close proximity, many of the cultural differences have slid along the visible racial lines rather than within or across races– in other words, it's safer to generalize within a race than within cultures/regions/states that span races. That said, there is still as much political and philosophical variation within each race as you may have here on earth within the most racially homogenous states in Europe or Africa.
For most of history, Illendor has been relatively isolated, visited primarily by sea traders. Intercourse with other races has varied based upon whatever nation the traders made contact with. Nations have risen and fallen in Illendor as in any other place, the most notable features being that a) they were almost entirely confined to Illendor, and b) they have for the most part all been multiracial nations. B is not entirely illogical; the races have their niches, and where those niches interact, the culture is multiracial; where the niches don't need to interact, there will be a predominance of one race. For instance, the Anghil naturally prefer eyries, and so are more plentiful in the mountains and above forests. They are inclined toward magical investigation and study. The Dondar, meanwhile, as creatures of the plains and deserts are patient and methodical with long memories and histories. The Siarrans are most adaptable, knitting the others together or tearing them apart with their human-like impatience, volatility, creativity, and spirit. Dragons, finally, are removed, distant, powerful, rare. They don't necessarily have a generalizable niche– the rare individuals are highly idiosyncratic. The generalization that can be made is that no generalization may be made. Young dragons are rarely seen, even for dragons… and when they are, they are often passing as far older, or as other races of their actual age.
Ages ago, dragons came to Illendor (some cultures forget or ignore that part). That was a time of high culture and technology (those same cultures claim that the golden age is simply the last thing the Illendi remember, and that they've forgotten their *native* youth and development). Eventually, however, that golden age ended (every culture gives a different reason for this). Much was forgotten over the years. Many wars were fought; borders and alliances shifted, and the Illendi expanded their territory to include all of the Illendor subcontinent. While pushing beyond that, the Illendi faced civilized quadrupedals (including humanoids) for the first time. Young and unsophisticated but possessing a passion and vigor beyond that of the Illendi, humanoids eventually rebuffed the Illendi enough for the far more advanced races to confine themselves to Illendor, a detente that held for thousands of years on both sides. Illendor, on the western and southern side of the mountains was for the Illendi; the rest was for the humanoids.
See Illendi Legends.